Conventional methods for charge reduction by using an auxiliary electron beam or by placing metal diaphrams on the sample surface in the SIMS analysis of insulators, are either inpractical for a wide variety of materials or not completely effective.
To solve these problems, the authors have developed a new insulator analysis method, combined with EBIC (Electron Bombardment Induced Conductivity) and formation of an electrically conductive path to reduce the sample surface charge. In this technique, a metal film about 40nm in thickness is deposited on the sample surface outside the analyzing area. Then electrons at an energy of about 3000 eV are bombarded both on the analyzing area and on the metal film. The EBIC layer is thus generated on the sample surface. The electron bombardment causes an electrically conductive path between the sample and the metal film, and therefore, charge accumulation on the sample surface is prevented.
It has been found that this technique can be used successfully for the surface analysis of a wide variety of insulating materials, including oxides, nitrides and organic thin films.